Can the Smudge Cells Be Counted As Lymphocytes in the Differential Leukocyte Counts Performed on Peripheral Blood Smears of Chronic Lymphocytic Leukemia Patients?

Objectives: Two characteristic peripheral blood smear findings of patients with chronic lymphocytic leukemia (CLL) are lymphocytosis and many smudge cells. Excluding smudge cells from manual differential (MDIFF), a common laboratory practice, yields unreliable results and consequently necessitates MDIFF on an albumenized blood smear. Since smudge cells represent remnants of fragile lymphoid cells, we sought to (1) test the hypothesis that reliable MDIFF results can be obtained from the nonalbumenized blood smear by including smudge cells and counting them as lymphocytes, and (2) confirm our previously reported finding that automated differential (ADIFF) results are also acceptable in these patients.